Diabetes: CGM signals

The new wave of diabetes posts on social media is built around a device that turns metabolism into a minute-by-minute graph. Continuous glucose monitors, or CGMs, track glucose in the fluid under the skin every few minutes. They were designed to help people with diabetes adjust food, exercise, and medication in real time, and the American Diabetes Association now recommends CGM metrics alongside A1C as a standard way to assess glycemic control (diabetesjournals.org). That steady stream of numbers makes certain patterns hard to ignore. One of the most common is the post-meal spike. In people without diabetes, glucose usually stays in a narrow band. A landmark CGM study of 153 healthy participants found a median of 96 percent of the day between 70 and 140 mg/dL, with only about 30 minutes a day above 140 mg/dL (academic.oup.com). So when patients share screenshots showing repeated surges well past 140 after ordinary meals, they are pointing at something real: their bodies are struggling to clear glucose efficiently. The same graphs also expose a second pattern that feels counterintuitive until you know the biology. Many people wake up high even after not eating all night. The ADA describes this as the dawn phenomenon. In the early morning, hormones such as cortisol and growth hormone tell the liver to release more glucose. A healthy pancreas matches that surge with enough insulin. In diabetes or insulin resistance, that compensation can fail, and glucose rises before breakfast even starts (diabetes.org). That is why the social-media shorthand about “morning highs mean insulin resistance” is directionally right, but still incomplete. Dawn phenomenon is common in both type 1 and type 2 diabetes, and the ADA says roughly half of people with either type experience it. It can also reflect too little overnight basal insulin, not just worsening insulin resistance (diabetes.org). A CGM trace can reveal the pattern. It cannot, by itself, explain the cause. The same caution applies to the posts claiming an A1C of 5.8 after going low-carb and adding Jardiance. An A1C of 5.8 percent is below the diabetes threshold and sits in the prediabetes range, which makes it an impressive result for someone starting with type 2 diabetes (cdc.gov). Jardiance, the brand name for empagliflozin, can help lower blood sugar and A1C in type 2 diabetes, but it is not a neutral add-on. The FDA-approved label warns about ketoacidosis, urinary and genital infections, dehydration, and rare but severe perineal infections (accessdata.fda.gov). Low-carb advice is closer to mainstream medicine than many people realize. The ADA’s nutrition guidance says reducing overall carbohydrate intake has the strongest evidence for improving glycemia, and low- or very low-carbohydrate eating plans are a viable option for select adults with type 2 diabetes (professional.diabetes.org; guidelinecentral.com). But the guideline does not prescribe a magic number like 50 to 70 grams a day for everyone. It pushes individualized plans, because the right amount depends on medications, kidney function, weight goals, and the risk of hypoglycemia. What the patient-shared CGM charts are really showing is simpler than the online chatter around them. They are making invisible physiology visible. A plate heavy in starch can send glucose climbing for hours. A liver can raise blood sugar before sunrise without a single bite of food. And a line on a screen can make the difference between vague advice and a concrete decision about what to eat for dinner, or whether that 6 a.m. rise started at 110 mg/dL or 170 (diabetesjournals.org; diabetes.org).